According to the United States Census Bureau, the CDP has a total area of 7.2 square miles (18.7 km2), of which 7.1 square miles (18.4 km2) is land and 0.12 square miles (0.3 km2), or 1.52%, is water.[4]

The northern boundary of the CDP is formed by Good Luck Road and Duckettown Road. The eastern boundary is formed with the city boundary of Bowie, then by Chestnut Avenue and High Bridge Road, then again by the boundary of Bowie. The southern boundary of Glenn Dale is formed by Annapolis Road (Maryland Route 450), and the western boundary follows the stream called Folly Branch, then Lanham-Severn Road (Maryland Route 564), then Greenbelt Road (Route 193), returning to Good Luck Road.[6]

There were 4,086 households out of which 45.7% had children under the age of 18 living with them, 62.6% were married couples living together, 13.9% had a female householder with no husband present, and 19.1% were non-families. 13.4% of all households were made up of individuals and 1.9% had someone living alone who was 65 years of age or older. The average household size was 3.08 and the average family size was 3.39.

In the CDP the population was spread out with 29.8% under the age of 18, 7.8% from 18 to 24, 32.2% from 25 to 44, 24.7% from 45 to 64, and 5.5% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 93.2 males. For every 100 females age 18 and over, there were 89.6 males.

The median income for a household in the CDP was $80,851, and the median income for a family was $85,448. Males had a median income of $53,484 versus $40,450 for females. The per capita income for the CDP was $27,920. About 2.6% of families and 4.5% of the population were below the poverty line, including 4.3% of those under age 18 and 9.9% of those age 65 or over.

The Glenn Dale Fire Association was formed to serve as a Volunteer Fire Department for the Glenn Dale area in 1928. Prior to that, there was no organized fire protection available for quite some distance around.

Glenn Dale Hospital was a tuberculosissanatorium. It is a large facility, consisting of 23 buildings on 210 acres (0.85 km2), that was built in 1934 and closed in 1982 due to asbestos. Though it is now closed and will be eventually demolished, for decades it was an important public health institution near Washington, D.C. Park Police patrol the hospital grounds regularly.

The hospital was featured in an award-winning Washington Post Magazine article, "Quarantined," on Dec. 10, 2006, by Leah Y. Latimer, former staff writer and author. The article detailed Latimer's mother's hospitalization there in the 1950s and the emotional fall-out for their family from then to the present. Latimer gave a lecture on the grounds of Glenn Dale on October 4, 2008. It was the first time the public was allowed on the grounds in almost 30 years. The unadvertised event drew more than 150 people. Latimer said she plans more lectures around the area, based on her continuing research and 110+ interviews.